A scientist is looking at anatomical structures in several different animal embryos Which is a question the scientist might ask to determine if the animals share a common ancestor? Do the embryos take the same amount of time to develop? Do the adult forms of the animals have analogous structures? Do the animals have the same structures as both embryos and adults? Do the animal embryos have similar structures that become different as they develop?

## Step 1<br />The problem is about understanding the concept of common ancestry in biology. The scientist is interested in determining if different animals share a common ancestor by examining their embryonic structures.<br /><br />## Step 2<br />The first option, "Do the embryos take the same amount of time to develop?", is not a valid question for determining common ancestry. The time taken for embryo development can vary greatly among different species and does not necessarily indicate a common ancestor.<br /><br />## Step 3<br />The second option, "Do the adult forms of the animals have analogous structures?", is also not a valid question for determining common ancestry. Analogous structures are those that perform similar functions but are not structurally similar, which does not indicate a common ancestor.<br /><br />## Step 4<br />The third option, "Do the animals have the same structures as both embryos and adults?", is not a valid question for determining common ancestry. The presence of the same structures in both embryos and adults does not necessarily indicate a common ancestor.<br /><br />## Step 5<br />The fourth option, "Do the animal embryos have similar structures that become different as they develop?", is a valid question for determining common ancestry. If embryos of different species have similar structures that become different as they develop, it suggests that these species share a common ancestor.